Biofuel containing levoglucosone and its production process from cellulose or starch using as a solvent a mixture of an ionic liquid and an alkyl alcohol

ABSTRACT

The product Biofuel is presented as a motor fuel consisting of levoglucosone pure or mixed with ethanol and or hydrocarbons. 
     Its production process from cellulose or starch uses in the first step, as a solvent and catalyst, a mixture of an alkyl alcohol, the ionic liquid N-alkyl imidazole hydrochloride and a small quantity of 37% concentrated hydrochloric acid. 
     In the second step, levoglucosone is extracted with butanol. As butanol also extracts some N-alkyl imidazole, this is washed out by extraction with hydrochloric acid. 
     Levoglucosone was identified by elemental analysis, NMR C13 and H and GC-MS.

1. FIELD OF INVENTION

Liquid biofuels from cellulose, ionic liquids, renewable energy, solventextraction from ionic liquids

2. BACKGROUND OF THE INVENTION

The world production of cellulose on land is 40 billion ton per year andthe stock of cellulose is 700 billion ton.

The world consumption of fossil fuels was in 2007, according to theInternational Energy Agency, 10 billion ton per year, which is 4 timesless than the production of cellulose.

The food production in the world is 3 billion ton per year, which is 13times less than the production of cellulose.

From these 3 numbers we conclude that, to take out from food, materialsto produce bio ethanol or vegetable oils for biodiesel would not solvethe problem of substituting fossil fuels, and would cause hunger.

On the other side, there are large surfaces of arable land, which arenot cultivated or which can only produce crops not suitable for food. Inthese surfaces, the production of cellulose from trees, sugar cane orbush is possible. On the other side, cellulose containing biomass is aside product of many food crops. This biomass is also a raw material forbiocell.

Sugar cane, has yields of 80-100 ton per hectar. In one ton of sugarcane there are about 80 kg of sugar, which may be converted to 50 kg ofbioethanol. Besides sugar there are 250 kg of cellulose andhemicellulose, which is not converted to liquid fuels. There are alsoabout 80 kg lignin, which may become a useful energy source in theconversion of cellulose to liquid biofuels.

Cellulose, hemicellulose and starch have been studied in the past aspossible sources of raw materials for liquid fuels and chemicals.

Wood itself is since thousands of years an energy source. Biomass isused today to produce electricity less than 1% of electricity, andelectricity represents only 17% of final energy consumption.

It is therefore important to find a process to convert cellulose inliquid fuels, suitable for energy supply to transportation and industry,which represent 95% of the consumption of crude oil.

The use of electricity for transportation is being made since a longtime with electric trains, fork lifts and cars, but its economy for mosttransports and the electricity availability are not competing withbiofuels from cellulose.

The substitution of fossil fuels is also important because of the carbondioxide which they produce by burning. Although cellulose also producescarbon dioxide by burning, the same quantity of carbon dioxide was takenbefore out of the atmosphere by photosynthesis in plants to producecellulose.

Although the carbon dioxide content on earth was up to 6000 ppm 100million years ago, it decreased to 250 ppm in the nineteen century andincreased again up to 380 ppm. These sharp increase in the last centuryis caused by burning fossil fuels and causes dramatic climate changesdue to the greenhouse effect.

As a consequence, to convert cellulose into a liquid fuel is sincedecades a challenge for scientists, because the existing cars and truckscould drive with such a liquid biofuel without major changes in themotor.

The exhausting oil reserves and the political dependency on unstablecountries producing oil is also a major problem today.

Producing electricity from nuclear or from renewable sources like wind,waves, rivers or photovoltaic, represents only 32% of electricityproduction. The rest is produced from fossil fuels. The substitution ofliquid fuels by electricity for transports creates a major problem ofstorage and transportation of electricity, which is technicallypossible, but far more expensive than the cellulose biofuels (Biocell).

Because cellulose is renewable, abundant and not producing carbondioxide by burning if photosynthesis is considered, there has beenrecent scientific work on following subjects (Bibliography 1 to 13):

-   -   dissolution of cellulose in ionic liquids instead of traditional        processes using water and organic solvents    -   hydrolysis of cellulose in ionic liquids    -   dehydration of fructose in ionic liquids to hydroxyl methyl        furfural    -   hydrogenation in organic solvents of hydroxymethyl furfural to        dimethyl tetrahydrofuran    -   isomerisation of glucose to fructose    -   In our previous work (PCT WO 2008 053284, PCT IB 2008 03313,        U.S. Pat. No. 1,235,6643, U.S. Pat. No. 1,247,6402) we found        that the hydrolysis of cellulose to glucose in N methyl imidazol        hydrochloride was always followed by dehydration of glucose and        the production of oligomers of glucose both by incomplete        hydrolysis of cellulose and by intermolecular dehydration of        glucose.    -   In our previous work we found that the dehydration intermediates        obtained from glucose easily react to oligomers by        intermolecular dehydration. These oligomers can not be easily        extracted with organic solvents.    -   from the ionic liquid phase we tried extraction with        3-pentanone, diethylether, disopropylether, buthanol. The best        solvent was butanol but it also extracted considerable        quantities of N.Alkyl imidazole.    -   In our U.S. Pat. No. 1,274,8425 application we filed for an        ionic liquid immiscible with water, which is trioctylamine        hydrochloride. However, the solubility of cellulose is very        poor.

2. DETAILED DESCRIPTION OF THE INVENTION

According to our previous experiments, we decided to use:

-   -   As an ionic liquid N-alkyl imidazole hydrochloride as it is by        far the best solvent for cellulose    -   We added a small amount of hydrochloric acid 37% in order to        catalyse the hydrolysis of cellulose to glucose    -   We also added a small amount of an alkylalcohol in order to        react with hydroxyl groups of glucose and by this way avoid the        oligomerisation by intermolecular dehydration between hydroxyls        of two different glucose molecules.    -   We found that by adding an alkyl alcohol the temperature could        be raised without any carbonisation of glucose. This means that        we stopped effectively the intermolecular dehydration.    -   The best solvent for extraction is in fact n-butanol, however it        has the inconvenient to extract also N-alkyl imidazole (boiling        temperature 198° C.), which in the GC-MS overlapps with        levoglucosone (boiling temperature 203° C.) and has a similar        boiling temperature. We solved the problem by washing out the        butanol extract with 37% hydrochloric acid, which takes out the        N-methyl imidazole.

Example

In a round bottom flask with reflux condenser were introduced:

N.methyl imidazole—41.5 g (0.50 mole)

Hydrochloric acid 37%—50.0 ml=60 g (0.60 mole)

The water was removed by vacuum destillation.

We added:

Methanol 20.0 g (0.60 mole) Hydrochloric acid 37% 5.0 ml (0.06 mole)Cellulose 4.0 g

This mixture was heated to 80-90° C. during 1 hour. After cooling, weadded 50 g of water to reduce viscosity and improve the immiscibility ofbutanol in the ionic liquid phase.

We then extracted with 3 portions of 50 ml butanol. The butanol extractwas extracted with two portions of 50 ml of hydrochloric acid 37% toremove N-alkyl imidazole from the butanol extract.

The residue was checked by NMR, FT-IR and elemental analysis. The yieldwas 87% of stechiometry. The stechiometry is 126 g of levoglucosone from168 g of cellulose.

The residue was found to be a levoglucosone almost pure:

BIBLIOGRAPHY

-   1. Jaroslaw Lewkowski, Synthesis, Chemistry and Applications of    5-Hydroxymethyl-furfural and its derivatives, Arkivoc, 2001, 17-54-   2. Claude Moreau, Annie Finiels, Laurent Vanoye, Dehydration of    fructose and sucrose into 5-hydroxymethylfurfural in the presence of    1-H-3-methyl imidazolium chloride acting both as solvent and    catalyst, journal of Molecular Catalysis A, 2006, 165-169-   3. Fred Shafizedh, Saccharification of lignocellulosic materials,    Pure and Appl. Chem., vol 55, No 4 pp 705-720, 1983-   4. Khavinet Lourvanij and Gregory Rorrer, Reaction rates for the    partial dehydration of glucose to organic acids in solid-acid    molecular sieving catalyst powders J. Chem. Tech. Biotechnol., 1997,    69, 35-44-   5. Yuri. Roman Leshkov, Christopher Barrett, Zehn Y. Liu, James A.    Dumesic, Production of dimethylfuran for liquid fuels from biomass    derived carbohydrates, Nature, Vol 447, 21 Jun. 2007, 982-   6. Acid in ionic liquid: an efficient system for hydrolysis of    lignincellulose, Changzhi Li et al. Green Chemistry, 17 Dec. 2007-   7. Cataklytic conversion of cellulose into Sugar alcohols Atsushi    Fukuoka et al. Angewandte Chemie, 2006, 45, 5161-5163-   8. Pyranone by pyrolysis of cellulose, Fred Shafizadeh, Pure &    Applied Chem, 1983, 55-4, 705-720-   9. Dissolution of cellulose with ionic liquids and its application—a    minireview, Shengdong Zhu et al, Green Chemistry, 2006, 8, 325-327-   10. WO 2008/053284 A1—Liquid biofuels containing dihydroxymethyl    furan, Pedro Correia, priority date 9 Mar. 2007.-   11. PCT IB 2008 03313, Liquid biofuels containing 2 methyl    tetrahydro pyran, Pedro Correia-   12. U.S. patent application Ser. No. 12/356,6643—Liquid biofuels    from cellulose, Pedro Correia-   13. U.S. patent application Ser. No. 12/748,425—Liquid biofuels from    cellulose using trioctylamine hydrochloride, Pedro Correia-   14. Simple chemical transformation of lignocellulosic biomass into    furan for fuel and chemicals, J. A.m. Chem. Soc. 2009, 131, (5),    1979-1985, Joseph Binder, Ronald Raines

1. A biofuel for motor cars containing levoglucosone pure or mixed withan alkyl alcohol and or hydrocarbons, its production process from woodor sugar cane itself or bagasse, cellulose or starch using as a solventa mixture of N-alkylimidazole hydrochloride, an alkyl alcohol and 37%hydrochloric acid, followed by an extraction with butanol followed by anextraction of the butanol extract with hydrochloric acid 37% to removesome N-Alkyl imidazole contained in the butanol extract, followed bydestillation of the washed butanol extract.
 2. In the process of claim 1where the ionic liquids N-alkyl imidazole contain as the alkyl groupmethyl, ethyl, propyl or butyl.
 3. In the process of claim 1 where thealcohol mixed with the ionic liquid is an alkyl alcohol with a number ofcarbon atoms from 1 to 10, preferably one carbon atom and where theproportion of alcohol to ionic liquid may vary from 1% to 30%, which canbe added at the start of the reaction or in small rates during thereaction.
 4. In the process of claim 1 where the amount of hydrochloricacid 37% added to the ionic liquid is 1% to 15%.
 5. In the process ofclaim 1 where the reaction time is 20 minutes to 180 minutes and thetemperature 80 to 250° C.
 6. In the process of claim 1 where beforeextraction of the ionic liquid reaction phase with butanol, the ionicliquid reaction phase is mixed with water to reduce the viscosity andthe miscibility of butanol with the ionic liquid.
 7. In the process ofclaim 1 where the butanol extracts are themselves extracted with 37%hydrochloric acid in order to remove any N-alkyl imidazol contained inthe butanol extracts
 8. In the process of claim 1 where thelevoglucosone, which has a boiling point of 203° C., is added directlyto diesel oil or gasoline, or is added with the addition of an alkylalcohol to make mixing easier, where the alcohol may contain 1 to 6carbon atoms